Free-hand aiming of a needle guide

ABSTRACT

A method for free-hand directing of a needle towards a target located in a body volume. The method includes the steps of producing an image of the target and the body volume, transmitting the image by means of an imaging detector to a display screen which communicates with a position sensing controller, sensing spatial orientation data of the imaging detector with respect to a reference, transmitting the spatial orientation data onto the display screen, placing the needle with a point thereof substantially pointing at the target sensing spatial orientation data of the needle with respect to the reference, transmitting the spatial orientation data of the needle to the position sensing controller, causing the position sensing controller, based on the spatial orientation data of the imaging detector and of the needle, to indicate on the display screen a trajectory of the needle point, and inserting the needle into the body volume towards the target in accordance with the trajectory indicated on the display screen.

FIELD OF THE INVENTION

The present invention relates to apparatus for performing needle biopsy,aspiration or injection by computer-aided controlled movement of amedical needle as it penetrates the body guided by an ultrasound orother imaging device.

BACKGROUND INFORMATION

Recently ultrasound diagnosis and therapy have become widely used, andmany surgical procedures have been replaced by gentler and less timeconsuming invasive needle therapy to the benefit of the patient. Interalia, ultrasonic imaging of maternal and fetal tissues has greatlyfacilitated prenatal diagnosis and treatment, and ultrasound imagingdevices greatly assist the physician in properly positioning a biopsyneedle to perform amniocentesis, cordocentesis and trans-abdominalchorionic sampling.

There are many different biopsy techniques and needles, and the needledepends on the type of patient and the target organ. The method mostwidely used today is the “free hand” technique, whereby the transduceris placed at a certain distance from the entry site of the needle andthe needle is manipulated with one hand. This technique requiresconsiderable skill and frequently repeated punctures, unless the targetis relatively large or located superficially. For these reasons andbecause manipulation of the needle as guided by an ultrasound imagegenerally requires both hands of the physician, much effort has beenmade to design and provide automatic devices for guiding the needle asdirected by the ultrasound beam.

Early developed devices include a needle attached to an ultrasoundtransducer housing, the needle being spaced from and articulated withrespect to the transducer. Such devices help the physician to manuallydirect the needle onto the desired biopsy location and to insert it tothe required depth. Such devices are, for instance, described in U.S.Pat. No. 4,899,756, issued to Sonec, and U.S. Pat. No. 4,911,173, issuedto Terwillinger. While all of these devices provided some movement ofthe needle guide and needle relative to the transducer, the physician isnevertheless significantly hampered in positioning the needle prior toand during insertion, as well as in re-positioning the transducer oncethe needle is inserted into the body.

Other commonly used devices include a transducer and a coaxial needleguide for manually positioning and inserting a needle. While thesedevices allow rapid and convenient guided biopsy, they have severalsignificant drawbacks: 1) The transducer must be placed directly overthe lesion, thereby requiring its sterilization or its draping by asterile covering. 2) The physician is forced to hold the transducer inone hand while using the other for sterilizing and anesthetizing thebiopsy site. 3) After inserting the needle, the transducer must be heldby an assistant or must be removed while the needle is maneuvered. 4)Multiple passes may necessitate re-positioning of the transducer andre-insertion of the needle. 5) The existing needle guides may make itdifficult to enter some superficial lesions. 6) Most transducers areflat, straight and relatively large, making some costal and subcostalapproaches difficult.

A completely automatic apparatus for computer controlled stereotacticbrain surgery is described in U.S. Pat. No. 5,078,140, issued to Kwoh.This apparatus suffers from the drawback that the needle or needle guideis integrally connected to the apparatus, thereby not permitting thephysician to choose the most suitable trajectory of the needle towardsthe target. In addition, the apparatus is highly complicated, expensiveand has to be calibrated for every operation.

Another device is an ultrasound directed needle guide, developed by thepresent Applicant, and disclosed in Israel Patent Application 107,523.It includes an ultrasound transducer and a needle, guide which holds asyringe and needle. Both the transducer and the needle guide are eachattached to a universally movable arm such that each may be placed on apatient's body in any desired position. The arms are vertically movablealong a vertical post and are provided with direction sensors configuredto signal the position of the attached instruments to computer means.The transducer transmits the image of the target to an imaging devicewhich in turn transmits the information to the computer means which isprogrammed to indicate the angular direction of the needle guide ontothe target and to direct the physician to place the needle in thecorrect position and direction on the patient's body.

SUMMARY OF THE INVENTION

The present invention seeks, inter alia, to improve the articulated armsystem disclosed in applicant's above mentioned Israel PatentApplication 107,523. The present invention does away with thearticulated arm and provides an improved “free-hand” technique for usingthe transducer and needle. The transducer is used to project on acomputer screen an image of a body portion to be treated, therebypermitting a physician to obtain on the screen the preferred needletrajectory as well as the actual position of the needle guide, insertedneedle and needle tip. The physician may then correct the actualtrajectory in accordance with the displayed information.

Optionally, the target in the body portion to be treated may be selectedand marked by the physician, such as with a cursor or other selectiondevice. In case the needle point does not lie in the plane of the targetimage, the physician either changes the position of the needle orrotates the imaging source or detector so as to obtain the coincidingplane on the display screen.

Unlike the prior art, the present invention provides a system formultiple, daily use by any physician who does not need to be speciallyskilled in the art.

In the present invention, the image may be produced by any known imagingapparatus, such as ultrasound, computerized tomography (CT) or X-ray,which will permit positioning of the ultrasound transducer or otherimaging detector at a distance from the actual entry site, therebypermitting the physician to place the needle in an optimal position.

It is noted that throughout the specification and claims the term“needle” encompasses any invasive device or tool and the term “needleguide” encompasses any device for holding and guiding a needle (orinvasive device or tool) as well as a needle (or invasive device ortool) with an integrated electronic system. The term “orientation”encompasses spatial position information with respect to six degrees offreedom, such as in a Cartesian system, position along any of threemutually perpendicular axes and angular rotation about any of the axes.The terms “orientation” and “position” are used interchangeably.

The present invention may use a variety of apparatus for sensing theorientation of the transducer and needle. One preferred embodiment ofapparatus for defining the position of the ultrasound transducer withwireless transmission includes mounting three small battery-operatedinfrared ultrasonic transponders on the ultrasound transducer intriangular alignment, each transponder having a different triggeringcode. A position sensing device is provided with three spaced-apartinfrared ultrasonic transceivers which emit coded infrared signals tothe respective transponder on the transducer and which receiveultrasonic responses from the respective transponder. The receivedsignals provide triangulation information for the controller tocalculate the exact position of the transducer in three-dimensionalspace.

A position sensing unit for the needle may work in a similar manner. Theposition sensing unit is provided with at least two transceiversconfigured to transmit wireless coded infrared signals to at least twotransponders mounted on the needle or needle guide which issue codedsignals back to the transceivers for calculating the needle position anddirection, and to transmit the data to the computing device for displayon the screen.

In another embodiment, both the transducer and the needle are providedwith transmitters which continuously emit signals which are received byseparate receivers. The received signals are transmitted to a computerfor computing the spatial orientation of the transducer and needle.

In yet another embodiment, the position and orientation control systemis based on magnetic field sensors, such as described in U.S. Pat. No.4,945,305 to Boyd, the disclosure of which is incorporated herein byreference. The system preferably includes a personal computer, magneticfield sensors, a magnetic transmitter, a magnetic receiver attached toan ultrasound probe, and a magnetic receiver attached to a needle. Adisplay screen shows an exact real-time ultrasound image of the targetedarea, and the needle and the needle trajectory are shown in accordancewith a color coded scheme. The color coded scheme indicates whether theneedle and the trajectory lie in the ultrasound plane or parallelthereto or intersect therewith.

It is appreciated that the orientation sensors of the transducer and theneedle may comprise many other types of sensing devices. For example,the sensors may comprise clusters of accelerometers which providespatial orientation data signals, such as described in U.S. Pat. No.4,839,836, the disclosure of which is incorporated herein by reference.

The ability of the present invention to provide marking of the targetenables the physician to mark the target, move on to other tasks, andthen return to the target at some later time, whether a needle iseventually inserted into the target or not. This auxiliary feature freesthe physician to do other tasks in the middle of an ultrasoundexamination, for example, and still be able to manipulate the ultrasoundtransducer to return to the target.

There is thus provided in accordance with a preferred embodiment of thepresent invention, a method for free-hand directing of a needle towardsa target located in a body volume, the method including the steps ofproducing an image of the target and the body volume, transmitting theimage by means of an imaging detector to a display screen whichcommunicates with a position sensing controller, sensing spatialorientation data of the imaging detector with respect to a reference,transmitting the spatial orientation data of the imaging detector to theposition sensing controller, displaying the spatial orientation dataonto the display screen, placing the needle with a point thereofsubstantially pointing at the target, sensing spatial orientation dataof the needle with respect to the reference, transmitting the spatialorientation data of the needle to the position sensing controller,causing the position sensing controller, based on the spatialorientation data of the imaging detector and of the needle, to indicateon the display screen a trajectory of the needle point, and insertingthe needle into the body volume towards the target in accordance withthe trajectory indicated on the display screen.

In accordance with a preferred embodiment of the present invention, themethod further includes the step of indicating on the display screen anactual progressive motion of the needle towards the target.

Additionally in accordance with a preferred embodiment of the presentinvention, the method further includes the step of indicating on thedisplay screen a deviation of the needle from the trajectory.

Further in accordance with a preferred embodiment of the presentinvention, the method further includes the step of adjusting a planardirection of the image so as to cause it to coincide with the positionof the needle point entering the target.

Still further in accordance with a preferred embodiment of the presentinvention, the method further includes the step of indicating to theposition sensing controller the position of the target by marking thetarget on the display screen.

In accordance with a preferred embodiment of the present invention, thesteps of transmitting the spatial orientation data of the imagingdetector and the needle to the position sensing controller are performedby means of wired communication.

Additionally the steps of transmitting the spatial orientation data ofthe imaging detector and the needle to the position sensing controllerare performed by means of wireless communication.

Further in accordance with a preferred embodiment of the presentinvention, the position sensing controller indicate on the displayscreen a two-dimensional trajectory of the needle point.

Still further in accordance with a preferred embodiment of the presentinvention, the position sensing controller indicate on the displayscreen a three-dimensional trajectory of the needle point.

In accordance with a preferred embodiment of the present invention, themethod further includes the step of displaying the spatial orientationdata of the needle onto the display screen.

Additionally in accordance with a preferred embodiment of the presentinvention, the step of producing an image is performed by ultrasoundimaging equipment.

Further in accordance with a preferred embodiment of the presentinvention, the step of producing an image is performed by X-Rayequipment.

Still further in accordance with a preferred embodiment of the presentinvention, the step of producing an image is performed by computerizedtomography equipment.

In accordance with a preferred embodiment of the present invention, thestep of producing an image is performed by magnetic resonance imagingequipment.

There is also provided in accordance with a preferred embodiment of thepresent invention, apparatus for free-hand directing of a needle havinga point towards a target located in a body volume, the needle beingmanipulated only by a hand of the user, the apparatus including aposition sensing controller which communicates with a display screen,imaging apparatus for producing an image of the body volume and thetarget, an imaging detector for transmitting the image onto the displayscreen, a probe orientation sensor for sensing spatial orientation dataof the imaging detector with respect to a reference, and a needleorientation sensor for sensing spatial orientation data of the needlewith respect to the target, whereby the position sensing controller,based on the spatial orientation data of the imaging detector and of theneedle, indicates on the display screen a trajectory from the needlepoint into the target.

In accordance with a preferred embodiment of the present invention, theimaging apparatus is ultrasound imaging apparatus and the imagingdetector is an ultrasound transducer.

Additionally in accordance with a preferred embodiment of the presentinvention, the probe orientation sensor communicates with the positionsensing controller via a triggering code.

Further in accordance with a preferred embodiment of the presentinvention, the needle orientation sensor communicates with the positionsensing controller via a triggering code.

Still further in accordance with a preferred embodiment of the presentinvention, the probe orientation sensor and the needle orientationsensor are electro-optical sensors.

In accordance with a preferred embodiment of the present invention, theprobe orientation sensor and the needle orientation sensor are magneticsensors.

Additionally in accordance with a preferred embodiment of the presentinvention, there is provided a three-dimensional viewing device forthree-dimensionally viewing the needle and the trajectory on the displayscreen.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be understood and appreciated more fully fromthe following detailed description, taken in conjunction with thedrawings in which:

FIG. 1 is a simplified block diagram of apparatus, constructed andoperative in accordance with a preferred embodiment of the presentinvention, for directing a needle having a point towards a targetlocated in a body volume, and including an ultrasound imaging system;

FIG. 2 is a simplified block diagram of apparatus, constructed andoperative in accordance with another preferred embodiment of the presentinvention, for directing a needle having a point towards a targetlocated in a body volume, and including an X-ray imaging system;

FIG. 3 is a simplified block diagram of apparatus, constructed andoperative in accordance with yet another preferred embodiment of thepresent invention, for directing a needle having a point towards atarget located in a body volume, and including a computerized tomography(CT) or magnetic resonance imaging (MRI) system;

FIG. 4 is a simplified pictorial illustration of directing the point ofthe needle towards the target, in accordance with a preferred embodimentof the present invention, using an ultrasound transducer and a needleguide each provided with three spaced-apart transponders;

FIG. 5 is a simplified illustration of a needle provided with twocoaxially mounted emitters or transponders;

FIG. 6 is a simplified illustration of a needle provided with threeemitters or transponders;

FIG. 7 is a simplified flow chart of a method for directing a needlehaving a point towards a target located in a body volume, in accordancewith a preferred embodiment of the present invention, using anultrasound imaging system;

FIG. 8 is a simplified illustration of apparatus for free-hand directingof a needle, constructed and operative in accordance with yet anotherpreferred embodiment of the present invention;

FIG. 9 is a simplified illustration of a computer screen displaying theneedle and needle trajectory in the same plane as the ultrasound plane;

FIG. 10 is a simplified illustration of a computer screen displaying theneedle and needle trajectory intersecting the ultrasound plane; and

FIGS. 11, 12 and 13 are simplified illustrations of needle apparatuswith a needle orientation sensor, constructed and operative inaccordance with three preferred embodiments of the present invention.

DETAILED DESCRIPTION OF THE DRAWINGS

Reference is now made to FIG. 1 which is a simplified block diagram ofapparatus 10, constructed and operative in accordance with a preferredembodiment of the present invention, for directing a needle 12 having apoint 14 towards a target 16 located in a body volume 18.

Apparatus 10 preferably includes a position sensing controller 20 whichcommunicates with a display screen 22, preferably via a computer 24.Imaging apparatus, such as an ultrasound imaging system 26, ispreferably provided for producing an image of target 16 and body volume18 by directing ultrasound waves thereto. An imaging detector, such asan ultrasound probe 28, preferably communicates with system 26 such asby means of a cable 29, for transmitting the image onto display screen22, preferably via computer 24. Unlike the prior art, probe 28 is notheld or guided by articulated means, but is manipulated “free-hand”.

Preferably disposed in probe 28 is a probe orientation sensor 30 forsensing spatial position data of probe 28 with respect to a reference,such as a given inertial reference origin. The position data ispreferably displayed on display screen 22, and a user looking at displayscreen 22 can direct needle 12 towards target 16. Optionally, the usermay indicate to position sensing controller 20 the position of target 16by marking target 16 on display screen 22. This marking may be done byany convenient method, such as by a keyboard, mouse, joystick, thumbwheel or touch screen. An advantage of the option of marking the target16 is described hereinbelow with reference to FIG. 7.

Needle 12 is preferably held fixed in a needle guide 32. Differentembodiments of needles and needle guides will be described in furtherdetail hereinbelow with reference to FIGS. 5, 6, 11, 12 and 13. Unlikethe prior art, neither needle 12 nor needle guide 32 is held or guidedby articulated means, but is manipulated “free-hand”.

Preferably a needle orientation sensor 34 is disposed in needle guide32, or alternatively needle 12, for sensing spatial orientation data ofneedle 12 with respect to the reference. Position sensing controller 20,based on the spatial orientation data of needle 12, indicates on displayscreen 22 a trajectory from needle point 14, the trajectory being animaginary straight ray emanating from needle point 14 along thelongitudinal axis of needle 12. Probe orientation sensor 30 and needleorientation sensor 34 may be in wired or wireless communication withposition sensing controller 20.

Reference is now made to FIGS. 2 and 3 which illustrate furtherembodiments of apparatus 10, wherein the imaging detector and apparatus,instead of an ultrasound probe and system, respectively comprise one ormore x-ray detectors 40, one or more x-ray radiation sources 42, and anx-ray continuous imaging system 44 (FIG. 2), and a CT or MRI detector50, a CT or MRI radiation source 52, and a CT or MRI scanner system 54(FIG. 3).

Reference is now made to FIG. 4 which illustrates directing point 14 ofneedle 12 towards target 16, in accordance with a preferred embodimentof the present invention, using ultrasound probe 28 and needle guide 32.It is appreciated that needle guide 32 may carry a syringe (not shown)for injection or tissue examination. In the illustrated embodiment,probe orientation sensor 30 and needle orientation sensor 34 eachcomprise an array of three spaced-apart transponders 60 and 62,respectively, in triangular alignment. Transponders 60 and 62 arepreferably electro-optical sensors which operate with infrared orvisible light. Transponders 60 and 62 preferably respond to codedsignals emitted by probe orientation sensor 30 and needle orientationsensor 34, respectively. Alternatively, only two responders 62 may beprovided in line with a vertical axis of needle 12 to define theposition of needle guide 32, there being no need for rotary adjustmentof needle 12.

While three transponders are illustrated in FIG. 4, it is appreciatedthat all three transponders may be alternatively packaged as onetransponder unit.

It is appreciated that needle orientation sensors may be mounted on theneedle in a variety of manners. Reference is now made to FIG. 5 whichillustrates a needle 70 provided with two coaxially mounted emitters ortransponders 72. Transponders 72 may be mounted on the body of needle 70by bending needle 70 into an approximate S-shape and attachingtransponders 72 to an upper portion 74 of the S-shape. Since thedistance of a needle point 76 from the transponders 72 is known, it ispossible to compute and to show the depth of entry of needle 70 ondisplay screen 22 (not shown).

Reference is now made to FIG. 6 which illustrates a needle 80 providedwith three emitters or transponders 82. Needle 80 is substantiallystraight, and transponders 82 are preferably fixedly attached to thebody of needle 80 in a fixed relationship with a needle point 84,thereby making it possible to compute and to show the depth of entry ofneedle 80 on display screen 22 (not shown).

Reference is now made to FIG. 7 which is a simplified flow chart of amethod for directing needle point 14 towards target 16, in accordancewith a preferred embodiment of the present invention, using ultrasoundimaging system 26.

Ultrasound system 26 produces an image containing the target and thisimage is sent to and displayed on display screen 22. Computer 24receives data from probe orientation sensor 30 and needle orientationsensor 34 and computes the position of both probe 28 and needle guide 32in relation to an inertial reference. Computer 24 also computes positionand orientation of the ultrasound image plane associated with probe 28.Since the two-dimensional projections of yaw, pitch and rotation ofprobe 28 appear on screen 22, the user can rotate probe 28 so as toplace needle point 14 into the viewed plane.

Computer 24 will now compute the trajectory of needle 12, typically inaccordance with well known geometric formulas. As stated above, thetrajectory is an imaginary straight ray emanating from needle point 14along the longitudinal axis of needle 12. The trajectory is displayed onscreen 22, and the user may then insert needle 12 towards target 16,after having shifted needle guide 32, if necessary. The path of needle12 during insertion is displayed on screen 22 and can be corrected incase of accidental deviation.

Optionally, the user may mark target 16 on screen 22 such as by means ofa keyboard, mouse, joystick, thumb wheel or touch screen. After markingtarget 16, computer 24 can calculate the spatial position thereof andtarget 16 may then be tracked according to known tracking methods of theart, such as by tracking it in contrast with the ultrasound image. Theability to track a target may be important in some situations when thetarget moves due to movement of the body organ in which it lies. Bymarking the target, the physician can be alerted to movement of thetarget and change the invasive procedure accordingly in order toprecisely pierce the target with the needle.

The foregoing description is a generalized description of a preferredmethod for directing the needle to the target. A more detaileddescription of another preferred method will be described hereinbelowfor the embodiment of FIG. 8.

Reference is now made to FIG. 8 which illustrates apparatus 90 forfree-hand directing of a needle 92, constructed and operative inaccordance with yet another preferred embodiment of the presentinvention. Apparatus 90 preferably includes a magnetic field positionand orientation sensing system, such as described in U.S. Pat. No.4,945,305 to Blood. The magnetic system preferably includes a magnetictransmitter 94, a magnetic receiver 96 attached to an ultrasound probe98. and a magnetic receiver 100 attached to needle 92. Apparatus 90preferably includes a computer 104 with a display screen 106. Displayscreen 106 preferably displays an exact real-time ultrasound image 108of a targeted area 110. Needle 92, in a preferred embodiment, is shownas a distinctly colored line, such as a blue line, even if needle 92 isoutside the ultrasound image 108. The expected trajectory 112 of needle92 is preferably displayed in accordance with a color scheme, so that aphysician may quickly and easily discern the relation of the needletrajectory 112 with the plane of the ultrasound image 108. An example ofsuch a color scheme is described hereinbelow with reference to FIGS. 9and 10.

A three-dimensional viewing device 170, such as a three-dimensionaleyeglasses device, may be provided for viewing needle 92 and trajectory112 three-dimensionally. Alternatively, computer 104 may be providedwith a three-dimensional imaging program for displayingthree-dimensional images of needle 92 and trajectory 112 on displayscreen 106. Such a program may, for example, form the three-dimensionalimages by displaying consecutive two-dimensional images of the objectscorresponding to views projected onto the left and right eyes.

As seen in FIG. 9, if trajectory 112 and needle 92 both entirely liewithin the ultrasound plane, then trajectory 112 is shown as a whitedotted line. As seen in FIG. 10, if trajectory 112 intersects theultrasound plane, a portion 160 of trajectory 112 which lies in front ofthe ultrasound plane is displayed as a red dotted line, a portion 162behind the plane is displayed as a green dotted line, and anintersection point 164 is displayed as a white empty circle. It isappreciated that these colors are merely examples, and other colorpatterns may be employed.

It is noted that if trajectory 112 is entirely in front of (or behind)the ultrasound plane, i.e., it is either parallel to the plane or theintersection point is out of view, then the entire trajectory 112 isdisplayed as a red (or green, if behind the plane) dotted line.

The distances between the dots of the dotted line may visually indicateto the physician an approximate angle of attack of needle 92 with theultrasound plane. The closer the dots, the more needle 92 isperpendicular to the ultrasound plane. The further the dots, the moreparallel needle 92 is to the ultrasound plane.

In addition, display screen 106 may optionally display a window 114intended to aid the physician in positioning and orienting probe 98 (notshown in FIGS. 9 and 10). Window 114 preferably contains a fixedrectangle 116, designating a top view of probe 98, and a movable line118 showing the projection of needle 92 as seen from above. Whilerotating or otherwise aligning ultrasound probe 98, the physician canobserve in window 114 how probe 98 and needle 92 relate to each other inspace as seen from above. Conversely, the image of needle 92 may befixed and rectangle 116 may show movement of ultrasound probe 98.

In FIG. 9, since needle 92 lies in the ultrasound image plane, line 118crosses horizontally through rectangle 116. In FIG. 10, since needle 92intersects the ultrasound image plane, line 118 pierces rectangle 116 atan angle thereto.

If the physician chooses to insert needle 92 so that it lies entirelywithin the ultrasound plane, as shown in FIG. 9 for example, then theprocedure is performed according to the following steps:

1. Select the needle insertion point.

2. Position the needle tip on the body at the point of insertion. Orientneedle 92 such that the expected trajectory 112 crosses the target.

3. Rotate ultrasound probe 98 so that the ultrasound plane contains boththe target and the whole of the needle and its expected trajectory. Oncesuch aligned, the expected trajectory is shown in white. The rotation ofprobe 98 may be optionally observed in window 114.

4. Insert needle 92, making sure that it stays in the ultrasound plane,i.e., its displayed image remains white. When the display indicates thatneedle 92 has entered the ultrasound image (i.e., the blue solid lineenters the image), observe needle 92 as imaged directly in theultrasound image.

5. When approaching the target, take extra caution to observe the actualneedle 92 and verify.

6. Insert needle 92 into the target if the orientations of the needletip and target are verified.

If in-plane insertion is impossible in the specific procedure, or if thephysician chooses to insert needle 92 so that it does not lie entirelywithin the plane of the ultrasound, the method is performed according tothe following steps:

1. Select the needle insertion point.

2. Position the needle tip on the body at the point of insertion. Orientneedle 92 such that the expected trajectory crosses the target, and thatthe white circle is on the target. This means that the trajectorycrosses the ultrasound plane exactly at the target.

3. Insert needle 92.

4. Verify the actual position of the needle 92 as follows:

a) Change the orientation of ultrasound probe 98, until the white circlemeets the tip of the blue solid line.

b) Observe the actual needle tip, as shown in the ultrasound image.

c) Once verified, return ultrasound probe 98 to the original position inaccordance with step 2.

5. If at the verification step 4, deviation of the needle is observed,(the needle tip is away from the tip of the blue line), mark the actualneedle tip. The computer will calculate a corrected trajectory, takinginto account the observed deviation. The blue line representing needle92 and the expected trajectory 112 will be redrawn according to thecalculated correction.

6. When approaching the target, take extra caution to observe the actualneedle and verify.

7. Insert needle 92 into the target if the orientations of the needletip and target are verified.

Reference is now made to FIGS. 11, 12 and 13 which are simplifiedillustrations of needle apparatus with a needle orientation sensor,constructed and operative in accordance with three preferred embodimentsof the present invention.

In FIG. 11, there is shown needle apparatus 120 which preferablyincludes a needle 122 and a connector 124, preferably standard, forconnection to a sampling device, such as syringe or other similar device(not shown). Apparatus 120 preferably further includes a body 126 onwhich is mounted a needle orientation sensor 128 for use with anorientation and position system, and an optional electric cable 130 forconnecting sensor 128 with external circuitry (not shown). Sensor 128 ispreferably embedded in body 126.

Optionally, body 126 may comprise two portions 134 and 136, joinedtogether by a fastener 132. Portion 134 is preferably permanentlyattached to the disposable invasive needle 122, and portion 136 includessensor 128 and optional cable 130, portion 136 being reusable andsterilizable before each use.

Reference is now made to FIG. 12 which illustrates needle apparatus 140,constructed and operative in accordance with another preferredembodiment of the present invention. Apparatus 140 is preferablysubstantially identical to needle apparatus 120 of FIG. 11. In needleapparatus 140, needle 122 is preferably fixed to a groove 141 formed inbody 126 by means of one or more clips 142. Typically needle 122 cannotbe removed from body 126 without breaking clips 142.

Reference is now made to FIG. 13 which illustrates needle apparatus 144,constructed and operative in accordance with yet another preferredembodiment of the present invention. Apparatus 144 is preferablysubstantially identical to needle apparatus 120 of FIG. 11, except thatconnector 124 of needle 122 is preferably attached to body 126 via amating connector 146. An additional connector 148 is preferably in fluidcommunication with needle 122, and is mounted on body 126. Connector 148may be used to connect apparatus 144 with a sampling device, such as asyringe or other similar device (not shown).

It is appreciated that various features of the invention which are, forclarity, described in the contexts of separate embodiments may also beprovided in combination in a single embodiment. Conversely, variousfeatures of the invention which are, for brevity, described in thecontext of a single embodiment may also be provided separately or in anysuitable subcombination.

It will be appreciated by persons skilled in the art that the presentinvention is not limited by what has been particularly shown anddescribed hereinabove. Rather the scope of the present invention isdefined only by the claims which follow.

What is claimed is:
 1. A method for free-hand directing of a needletowards a target located in a body volume, the method comprising thesteps of: producing an image of said target and said body volume from animaging detector; transmitting said image produced by said imagingdetector to a display screen which communicates with a position sensingcontroller; sensing spatial orientation data of said imaging detectorwith respect to a reference; transmitting said spatial orientation dataof said imaging detector to said position sensing controller;determining the position of said image in accordance with said spatialorientation data of said imaging detector; placing said needle with atleast a portion thereof substantially pointing at said target; sensingspatial orientation data of said needle with respect to said reference;transmitting said spatial orientation data of said needle to saidposition sensing controller; causing said position sensing controller,based on said spatial orientation data of said imaging detector and ofsaid needle, to indicate on said display screen at least one of thetrajectory or the position of at least a portion of said needle withrespect to said displayed image of said body volume.
 2. The methodaccording to claim 1 and further comprising the step of indicating onsaid display screen an actual progressive motion of said needle towardssaid target.
 3. The method according to claim 1 and further comprisingthe step of indicating on said display screen a deviation of said needlefrom said trajectory.
 4. The method according to claim 1 and furthercomprising the step of adjusting a planar direction of the image so asto cause it to coincide with the position of the needle point enteringthe target.
 5. The method according to claim 1 and further comprisingthe step of indicating to said position sensing controller the positionof said target by marking said target on said display screen.
 6. Themethod according to claim 1 wherein said steps of transmitting saidspatial orientation data of said imaging detector and said needle tosaid position sensing controller are performed by means of wiredcommunication.
 7. The method according to claim 1 wherein said steps oftransmitting said spatial orientation data of said imaging detector andsaid needle to said position sensing controller are performed by meansof wireless communication.
 8. The method according to claim 1 whereinsaid position sensing controller indicates on said display screen atwo-dimensional trajectory of said needle point.
 9. The method accordingto claim 1 wherein said position sensing controller indicates on saiddisplay screen a three-dimensional trajectory of said needle point. 10.The method according to claim 1 and further comprising the step ofdisplaying said spatial orientation data of said needle onto saiddisplay screen.
 11. The method according to claim 1 wherein said step ofproducing an image is performed by ultrasound imaging equipment.
 12. Themethod according to claim 1, wherein said step of producing an image isperformed by X-Ray equipment.
 13. The method according to claim 1,wherein said step of producing an image is performed by computerizedtomography equipment.
 14. The method according to claim 1, wherein saidstep of producing an image is performed by magnetic resonance imagingequipment.
 15. The method of claim 1, additionally comprising, insertingsaid needle into said body volume in accordance with said position orsaid trajectory of said at least a portion of said needle indicated onsaid display screen.
 16. The method of claim 1, wherein said at least aportion of said needle includes a predetermined point along said needle.17. The method of claim 1, wherein said at least a portion of saidneedle includes the tip of said needle.
 18. The method of claim 1,wherein said at least a portion of said needle includes at leastsubstantially all of said needle.
 19. Apparatus for free-hand directingof a needle towards a target located in a body volume, said needle beingmanipulated only by a hand of a user, said apparatus comprising: aposition sensing controller which communicates with a display screen; animaging apparatus for producing an image of said body volume and saidtarget; an imaging detector for transmitting said image onto saiddisplay screen; a probe orientation sensor attached to said imagingdetector for sensing spatial orientation data of said imaging detectorwith respect to a reference; and a needle orientation sensor attached tosaid needle for sensing spatial orientation data of said needle withrespect to said reference; and said position sensing controllerconfigured for determining the position of said displayed image fromsaid spatial orientation data of said imaging detector and configuredfor indicating on said display screen at least one of the trajectory orthe position of at least a portion of said needle with respect to saiddisplayed image of said body volume, based on said spatial orientationdata of said imaging detector and of said needle.
 20. Apparatusaccording to claim 19 wherein said imaging apparatus is ultrasoundimaging apparatus and said imaging detector is an ultrasound transducer.21. Apparatus according to claim 19 wherein said probe orientationsensor communicates with said position sensing controller via atriggering code.
 22. Apparatus according to claim 19 wherein said needleorientation sensor communicates with said position sensing controllervia a triggering code.
 23. Apparatus according to claim 19, wherein saidprobe orientation sensor and said needle orientation sensor areelectro-optical sensors.
 24. Apparatus according to claim 19, whereinsaid probe orientation sensor and said needle orientation sensor aremagnetic sensors.
 25. Apparatus according to claim 19 and comprising athree-dimensional viewing device for three-dimensionally viewing saidneedle and said trajectory on said display screen.
 26. Apparatusaccording to claim 19, wherein said imaging apparatus is computerizedtomography apparatus and said imaging detector is a computerizedtomography scanning head comprising a CT radiation source and a CTdetector.
 27. Apparatus according to claim 19, wherein said imagingapparatus is magnetic resonance imaging apparatus and said imagingdetector is a magnetic resonance imaging scanning head comprising a MRIradiation source and a MRI detector.
 28. Apparatus according to claim19, wherein said imaging apparatus is X-Ray apparatus and said imagingdetector is a X-Ray scanning head comprising a X-Ray radiation sourceand a X-Ray detector.
 29. The apparatus of claim 19, wherein said atleast a portion of said needle includes a point along said needle. 30.The apparatus of claim 19, wherein said at least a portion of saidneedle includes the tip of said needle.
 31. The apparatus of claim 19,wherein said at least a portion of said needle includes at leastsubstantially all of said needle.
 32. The apparatus of claim 19,additionally comprising: a connector adapted for attachment to saidneedle, said connector for connection to a sampling device.
 33. Anapparatus for directing of a needle with respect to a target located ina body volume, comprising: a needle; a needle orientation sensorattached to said needle which senses orientation of said needle withrespect to a reference; an imaging detector for transmitting an image toa display device; a probe orientation sensor attached to said imagingdetector for sensing orientation of said imaging detector with respectto said reference; and a position sensing controller in operativecommunication with said needle orientation sensor and said probeorientation sensor configured for determining the position of saiddisplayed image from said spatial orientation data of said imagingdetector and configured for placing a representation of at least one ofthe trajectory or the position of at least a portion of said needle onsaid image on said display device, based on said orientations of saidimaging detector and said needle with respect to said reference.
 34. Theapparatus of claim 33, wherein said at least a portion of said needleincludes a predetermined point along said needle.
 35. The apparatus ofclaim 33, wherein said at least a portion of said needle includes thetip of said needle.
 36. The apparatus of claim 33, wherein said at leasta portion of said needle includes at least substantially all of saidneedle.
 37. The apparatus of claim 33, additionally comprising: aconnector adapted for attachment to said needle, said connector forconnection to a sampling device.